Samples and Populations

When we obtain data from the whole population, we conduct a ____________?

A survey obtains data from a _____________ of the population.

A school conducts an election for the new school captain. Every teacher and student in the school casts a vote. Is this an example of a census or a survey?

State the type of sampling used in the following scenario:

Selecting every 50th name from an alphabetical list of residents.

Why should samples be randomly selected?

• for control

• to reduce bias

• so we don't get the same answers from everyone

Determine if the following study is biased.

Carlos wants to know the favourite sport of people at his school so he asks his baseball team.

• Biased

• Unbiased

Determine if the following study is biased.

A public library asked every 10th person who entered to name the type of book they were getting.

• Biased

• Unbiased

A factory produces 2520 DVD players every day. How many DVD players are tested daily if the factory tests a systematic sample of every 12th DVD player?

1 253 982 people are estimated to currently be living in the Brisbane City Council region. Roughly how many people would we need to survey, to have an unbiased sample of the population? (Round your answer to the nearest whole number)

In a group of 480 students, 160 are primary students and 320 are secondary students. A stratified sample of 120 is to be selected from the group based on year level. How many primary students should be selected?